Combustion enhancement system

ABSTRACT

An apparatus and method for enhancing the efficiency of a combustion process and thereby reducing undesirable emissions in which a solid combustion enhancing substance is converted into a highly dispersed, gas-transportable state at a controlled rate and is subsequently conveyed into the zone of combustion. The use of a substance in its solid state eases handling and avails highly effective materials for combustion and enhancement while the necessary conversion of the substance from one state to another enables a high degree of control as to its rate of addition to the combustion process. The substance&#39;s highly dispersed state when it enters the combustion process maximizes its effect.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a method and apparatus forincreasing the efficiency of hydrocarbon combustion processes to therebyreduce the production of undesirable emissions. More particularly, theinvention provides an apparatus and method for conveying, at a preciselycontrollable rate, minute quantities of a combustion enhancing substancedirectly to the site of combustion.

2. Description of the Prior Art

A wide variety of methods and devices have been disclosed that areintended to enhance the combustion of hydrocarbon fuels by introducingvarious substances into the combustion process. The intent is to improveefficiency, i.e. to increase the amount of the fuel's inherent chemicalenergy that is converted into thermal energy, and simultaneously todecrease undesirable emissions including unburned or incompletely burnedhydrocarbons, carbon monoxide, and nitrogen oxides. Bringing about amore complete oxidation of the hydrocarbons and carbon monoxide has thesimultaneous effect of increasing efficiency and decreasing theundesirable emissions.

A wide variety of substances have been relied upon to perform a varietyof functions in the interests of enhancing combustion processes.Coreactants, catalysts, and as well as compounds subject to operatingmechanisms not fully understood have been introduced into combustionprocesses via the fuel supply, the oxidant supply or into the fuel andoxidant comixture just prior to or during actual combustion.

The viability of a particular system depends not only on the efficacy ofthe substance utilized, but also on how easily the substance can behandled as well as how easily the substance can accurately be deliveredinto the combustion process in a highly dispersed form at the properlevels. Substances have been identified that are effective at ppb-rangeconcentrations but systems attempting to deliver such smallconcentrations in highly dispersed form have suffered from complexityand fail to maintain proper concentration levels. Maintaining the properconcentration level is important not only in terms of the economicconsiderations involved, but also because the presence in the combustionprocess of too little as well as too much active substance may diminishits enhancing effect.

Platinum is an example of a substance known to promote combustionreactions at concentrations as low as 80 ppb of fuel. The extremely lowconcentration requirement precludes simply finely dividing the metal forgradual introduction into a combustion process not only in terms ofactually being able to achieve 80 ppb, but also in terms of sufficientlydispersing such a small quantity of solid material amongst a typicallyhighly dispersed fuel/oxidant combustible mixture. Platinum hasextremely high melting and boiling points and therefore a commensuratelylow vapor pressure which hinders attempts to introduce the substanceinto a combustion process as a vapor. As a result of platinum's physicalproperties, direct addition of metallic platinum has not provided aviable approach to combustion enhancement. Various compounds of platinumhave therefore been considered as vehicles for introducing a highlydispersed form of platinum into a combustion process, lots of attentionhaving been focused on solutions of such compounds. While systems havebeen proposed that do thereby succeed in delivering the desiredconcentrations of highly dispersed platinum into a combustion process,practical problems prevail that make such systems complex andnonetheless unable to maintain a steady delivery rate. Moreover, thedisclosed systems appear incapable of quickly and easily adjusting forchanging feed rate requirements. A typical example of a prior art systemis that provided by B. J. Robinson, in U.S. Pat. No. 4,295,816 wherein asystem is described that introduces minute quantities of platinum into adiesel or gasoline engine's combustion chamber. A small quantity ofcombustion air is bubbled through a platinum compound containing aqueoussolution at a constant rate to generate a catalyst containing mist whichis then gradually drawn into the combustion chamber. This burstingbubble technique reportedly serves to draw out the catalytically activesolute without significantly depleting the solvent, although some of thesolvent is subject to evaporation. It would appear to be extremelydifficult to maintain a constant platinum compound concentration withinthe aqueous solution which would have a commensurate effect on theamount of platinum transferred to the mist generated by the bubblingaction. It is further conceivable that factors such as air temperature,solution temperature, and atmospheric pressure and humidity could effectthe transfer rate of the platinum compound from solution to the mist.Less than the optimal catalyst concentration level would diminish thedesired combustion enhancing effect, while greater than optimalconcentrations would be wasteful and additionally, may in fact have adeleterious effect on the performance of the system as well. Theinaccuracy of the delivery system as well as the problems attendant withthe handling of solutions which require periodic concentrationadjustment provides a typical example of the disadvantages associatedwith prior art systems. Similar systems have been proposed for a widevariety substances thought to have a combustion enhancing effectincluding rhenium compounds.

Additional considerations are of critical importance in automotiveapplications wherein the combustion enhancing substance must not only beconsumed at an economical rate, but the bulk and weight of the substancemust be such so as to provide reasonably long replenishment intervals.Further, the combustion enhancing substance handling and delivery systemshould be adaptable to existing engine and vehicular designs. In thecase of aftermarket applications, the system must further be readilyadaptable to particular vehicles already in service.

The prior art has failed to provide a hydrocarbon combustion enhancingsystem capable of delivering minute quantities of an easily handleableand effective combustion enhancing substance at a precisely controllablerate for extended periods of time in an economical fashion. Moreover,systems have not been disclosed that provide for extended service cyclesand which are readily adaptable to existing combustion processes.

SUMMARY OF THE INVENTION

The present invention overcomes the above noted shortcomings of theprior art to provide a method and apparatus for introducing minutequantities of a highly dispersed combustion enhancing substance into acombustion process. The method relies on the selection of a combustionenhancing substance that exists as an air stable solid under ambientconditions and is therefore easily handled and stored. Further, thesubstance is selected for its convertiblility directly from its solidstate into a highly dispersed, gas-transportable state, preferablysimply by heating to within an easily attainable and easily maintainabletemperature range. By obviating the need to form a solution, the presentinvention overcome the difficulties associated with transferring asolute to a highly dispersed, gas-transportable state and additionallyovercomes the difficulties associated with the handling of liquids andfluctuating solute concentrations.

The method of the present invention calls for the solid substance to bedirectly converted to its highly dispersed, gas-transportable state asby sublimation. Once the substance is in its gaseous form, it istransported to the combustion zone preferably by a flow of gas eithercontemporaneously formed with the conversion of the substance or by aflow of combustion air being inducted into the combustion process. Bycontrolling the amount of substance allowed to convert into itsgas-transportable form, the concentration of the substance participatingin the combustion process is effectively controlled. The inventionadditionally calls for sensor feedback mechanisms to control theconversion rate of the substance from its solid to its gas transportablestate as a function of either fuel consumption rate or emission rate oras a function of indirect indications of such parameters.

The compound bis-acetylacetonato platinum has been found to beespecially well adapted for the practice of the present invention. Thesubstance, in its finely divided powdered form, is metered onto a heatedsurface where it sublimes to be carried off into the combustion process.More particularly, the powder is transferred from a hopper onto asurface, maintained at about the substance's sublimation temperature andwell below its decomposition temperature, via a positive displacementpump driven by a variable speed motor. The motor speed is controlled asa function of fuel consumption rate or the emission rate from thecombustion process of certain compounds. By controlling the temperaturesthe substance is subjected to, it remains highly dispersed andgas-transportable and can be swept into the combustion zone bycombustion air.

The present invention additionally provides for the comixture of a drypowdered filler material with the substance to act as a diluent andoptionally to create propulsive gas for transporting the activesubstance into the combustion zone. By selecting a filler material ofcomparable particle size and density, separation of the intermixedpowders during handling is substantially precluded. By further selectingthe material to have a sublimation temperature comparable to thetemperature at which the active substance is converted to itsgas-transportable state, a contemporaneous creation of gas pressure andflow is created. Bis-acetylacetonato platinum and vanillic acid havebeen found to be a compatible active substance/filler combination.

Other features and advantages of the present invention will becomeapparent from the following detailed description, taken in conjunctionwith the accompanying drawings, which illustrate by way of example, theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates a combustion enhancing substancedelivery system according to the present invention interconnected to aninternal combustion engine; an

FIG. 2 is an enlarged view of the circled area 2 of FIG. 1 showingdetails of the metering mechanism.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

The Figures schematically illustrate an apparatus with which the methodof the present invention is practiced. The apparatus enables minutequantities of a combustion enhancing substance, originally in an easilyhandled solid state, to be introduced into an internal combustionengine's combustion chamber in a highly dispersed state at a preciselycontrolled rate. The substance's presence during the combustion processincreases the engine's power output, decreases the fuel consumption rateand decreases undesirable emissions in the engine's exhaust, includingcarbon monoxide and incompletely burned as well as unburnedhydrocarbons.

FIG. 1 schematically illustrates an internal combustion engine 12 towhich the combustion enhancing apparatus 14 of the present invention isinterconnected. The illustration shows combustion air 15 drawn inthrough an air intake duct 16 and fuel line 18 from fuel source 20feeding the engine. A mixture of the fuel and air is burned in theengine's combustion chamber and results in the rotation of output shaft21. The resulting gases 23 are expelled from the engine via exhaust duct22. FIG. 1 further shows the combustion enhancing apparatus 14 toinclude a hopper 24 for containing a powdered solid 25, a meteringmechanism 26 driven by a variable speed motor 28, a conversion chamber30 and a duct 32 leading to the engine intake system 16. Controller 34adjusts the speed of variable speed motor 28 in response to any of anumber of various sensor inputs 35-38 or alternatively by a manualsetting 39.

Hopper 24 is sized in accordance with the rate at which powderedmaterial 25 is consumed so as to provide a supply thereof for asubstantial period of time. The hopper's walls 40 are angledsufficiently to ensure a flow of the dry material towards a centrallylocated exit orifice at the hopper's base.

Metering system 26 is positioned within the hopper's exit orifice. Arotatable ball element 42 sealingly engages inset 44 to prevent theescape of material. Ball 42 has a centrally located bore 46 therein inwhich piston 48 is free to reciprocate. Piston 48 is sized to provide aclose tolerance fit with bore 46 and is of a length selected to be lessthan the diameter of ball 42. Piston 48 has a laterally positioned,centrally located void 50 formed therein into which eccentricallypositioned cam element 54 of rod 52 is received. Ball element 42 is freeto rotate about rod 52 which is held in position by bushing 56 at oneend and held fixed at the other. Shaft 58 is securely affixed to ball 42at one end and driven by variable speed motor 28 at its other end. Shaft58 and rod 52 define the axis 59 about which ball 42 is rotatable. Thedescribed mechanism serves to impart a reciprocating motion to piston 48upon rotation of ball element 42.

Situated directly below metering system 26 is conversion chamber 30which includes a heatable surface 60 positioned so that any materialtransferred by metering mechanism 26 from hopper 24 comes into contactwith the surface. Heating element 62 maintains the temperature ofheatable surface 60 within allowable limits via a controller (notshown). Pressure equalization line 64 sets the conversion chamber 30 incommunication with hopper 24 to prevent a build-up of a pressuredifferential which may otherwise affect the accuracy of the meteringsystem. Vent 66 may optionally be included to vent conversion chamber 30to the atmosphere. Duct 32 interconnects conversion chamber 30 with theintake duct 16 of engine 12. Gaseous or gas transportable componentswithin chamber 30 are thereby drawn into the engine's combustionchamber.

The speed of variable speed motor 28 is controlled by controller 34which is responsive either to manual input 39 or any of a variety inputsprovided by sensors 35-38 monitoring parameters associated with theengine's performance. For example, sensor 35 measuring intake manifoldpressure gives an indirect indication of the amount of fuel beingconsumed. Additionally, by considering engine rpm (sensor 36) a moreaccurate indication of engine load is provided to more accuratelyestimate the fuel consumption rate. Directly measuring fuel flow viasensor 38 provides the most accurate indication of fuel consumption.Controller 34 is programmed to increase the speed of motor 28 as afunction of increased fuel consumption regardless of which sensor isrelied upon. Alternatively, sensor 37 is employed to measure theemission rate of certain exhaust constituents. Controller 34 isprogrammed to adjust the motor speed accordingly.

It has been found that bis-acetylacetonato platinum is a compoundespecially well suited to the process of the present invention and isthe substance utilized in the preferred embodiment. The compound iseasily handled as a solid, and is readily converted into a highlydispersed gas-transportable state upon heating. The preferred embodimentof the present invention utilizes this particular platinum compound inits finely powdered form. The substance's published sublimationtemperature is 338° F. and decomposition occurs at 788° F. However, ithas been found that by heating bis-acetylacetonato platinum to between260° F. and 310° F. an adequate conversion rate into its highlydispersed, gas-transportable state is achieved while temperatures above310° F. cause the substance to deposit on the heating surfaces andsubsequent contact with surfaces at above 400° F. induces the substanceto plate out.

In operation, variable speed motor 28 rotates at a speed controlled bycontroller 34. Drive shaft 58 extending from motor 28 rotates ball 42.With each rotation of ball 42, piston 48 accommodated thereinreciprocates within its bore 46 to form a void while at the top of itscycle and to completely fill the void while at the bottom of its cycle.Ball 42 thereby picks up a precisely defined quantity of dry powderedmaterial 25 from within hopper 24 and expels such material downwardlywhen rotated 180°. Two such cycles result from every rotation of theball.

Material 25 expelled from ball 42 drops onto heated surface 60 which ismaintained at the appropriate temperature by controlled heating element62. The dry material sublimes or is otherwise directly converted into ahighly dispersed, gas-transportable state at which point it is ready tobe drawn into or otherwise injected into a combustion process such asexemplified by the illustrated and described internal combustion engine.Normally, simply tapping into such an engine's intake manifold providesan adequate means for delivery, while a supercharged system will requiremoving such tap to a location subject to sub-atmospheric pressures oralternatively, adequately pressurizing conversion chamber 30.

Controller 34 tailors the material's conversion rate into its highlydispersed, gas-transportable state, preferably, as a function of theengine's fuel consumption rate. Directly measuring fuel flow (sensor 38)provides the most accurate indication of the fuel consumption rate, butthe typically encountered, relatively slow flow rates or thecomplexities introduced by a high pressure recirculating fuel systemoften make such an approach unviable. Alternatively, the fuelconsumption rate is determined by intake air flow and further may beestimated by intake manifold pressure (sensor 35) In normally aspirated,throttled engines, the fuel consumption rate is fairly well approximatedby the inverse of the manifold vacuum, i.e. the higher the measuredvacuum, the lower the fuel consumption rate. By additionally providinginformation as to the engines speed (sensor 36) the intake vacuuminformation can be modified to more accurately determine fuelconsumption rate. Controller 34 processes this information regardingfuel consumption rate and based on the required addition rate specificto the particular combustion enhancing substance 25 within hopper 24,determines and sets the appropriate motor speed.

Alternatively, controller 34 is responsive to the emission rates ofcertain compounds, found in the engine's exhaust (sensor 37). This typeof feedback system provides more direct control of the resultsultimately desired. By directly measuring hydrocarbon content or carbonmonoxide content, the controller appropriately programmed, can moreimmediately fine tune the conversion rate of the combustion enhancingsubstance. Measuring the exhaust's O₂ content can similarly provide anindication of the efficiency of the combustion process.

EXAMPLE

A combustion enhancement system was constructed according to the presentinvention in which a conical funnel, having walls sloped at 60° wasutilized as the hopper (24). The metering mechanism utilized a 1.00"diameter metering ball accommodating a 0.25" diameter piston element,0.875" long. This assembly provided a 0.125" deep, 0.25" diameter voidof 0.00614 in³ volume for transfer of 0.0122 in³ of material from thehopper to the conversion chamber with every revolution.

The heated surface (60) within the conversion chamber measuredapproximately 2.5"×6.0" and was maintained at 300° F. with anappropriately interconnected temperature controller and thermocouple.

Vanillic acid was intermixed with bis-acetylacetonato platinum toprovide 190:1 dilution by volume. The materials were blended, ground andpassed through a 100 mesh screen and subsequently introduced into thehopper.

A 0.25" I.D. delivery hose interconnected with the intake manifold of a3.8 hp, single cylinder 4-stroke diesel engine deplacing 0.199 litersand driving a 2000 watt generator. A sensor monitored the engine'smanifold vacuum and the controller (34) served to adjust the motor'sspeed to rotate the metering ball element at a maximum of 0.5 rpm atminimum manifold vacuum and with six discrete, evenly spaced slowerspeeds as maximum vacuum is attained.

The resulting test data showed the hydrocarbon content in the exhaust todecrease by 40-50% with a 1600 watt load placed on the generator.Qualitatively, it was observed that the exhaust turned from black towhite. Upon interrupting the conversion of the combustion enhancingsubstance into its highly dispersed, gas-transportable state, theengine's emission levels quickly returned to their original level andthe exhaust smoke once again turned darker.

While a particular form of the invention has been illustrated anddescribed, it will also be apparent to those skilled in the art thatvarious modifications can be made without departing from the spirit andscope of the invention. It is not intended that this invention belimited to a particular type of internal combustion engine or even anyspecific combustion process. Further, no limitation is intended withrespect to any particular combustion enhancing substance. Accordingly,it is not intended that the invention be limited except as by theappended claims.

What is claimed i:
 1. A device for enhancing the efficiency of acombustion process in which a hydrocarbon fuel is consumed in acombustion zone in order to diminish the emission therefrom ofundesirable compounds including carbon monoxide and incompletelyoxidized hydrocarbons, comprising:means for storing a preselectedcombustion enhancing substance in its solid state selected for itsstability to significantly enhance said combustion process at ppb-rangeconcentrations and for its convertibility into a highly dispersed,gas-transportable state; means for variably converting at a controllablerate said combustion enhancing substance directly from its solid stateinto its highly dispersed, gas-transportable state; and means fortransporting said converted substance, substantially immediately uponits conversion, to said combustion zone.
 2. The device of claim 1,further comprising means for determining the fuel's consumption rate andmeans for controlling the conversion rate of the combustion enhancingsubstance from its solid state to its highly dispersed,gas-transportable state as a function of said determined consumptionrate.
 3. The device of claim 1, further comprising means for determiningthe emission rate of selected compounds from the combustion process andmeans for controlling the conversion rate of the combustion enhancingsubstance from its solid state to its highly dispersed,gas-transportable state as a function of said determined emission rate.4. The device of claim 1 wherein said transporting means comprises a gasflow passing through said converted substance in its highly dispersed,gas-transportable state and into said combustion zone.
 5. The device ofclaim 4 wherein said gas flow comprises combustion air for saidcombustion process.
 6. The device of claim 1 wherein said transportingmeans comprises a gas generated contemporaneously with the conversion ofsaid combustion enhancing substance into its highly dispersed,gas-transportable state that is conducted into the combustion zone. 7.The device of claim 1 wherein said converting means serves to subjectsaid solid combustion enhancing substance to heat.
 8. The device ofclaim 7 wherein said subjecting of said solid combustion enhancingmaterial causes it to sublime.
 9. The device of claim 7 wherein saidcombustion enhancing substance comprises bis-acetylacetonato platinumand said converting means serves to subject said solid substance to atemperature of between about 260° and 310° F.
 10. The device of claim 9further comprising means for preventing said substance in its highlydispersed, gas-transportable state from contacting surfaces exceedingabout 330° F. during its transport into the combustion zone.
 11. Thedevice of claim 9 wherein said bis-acetylacetonato platinum is stored asa fine powder in a hopper, and the device further comprises a positivedisplacement pump means for transferring a preselected volume of powderfrom said hopper onto a heated surface held at between about 260° and310° F.
 12. The device of claim 11 wherein said positive displacementpump is driven by a variable speed motor.
 13. The device of claim 12further comprising means for determining fuel consumption rate and meansfor varying said motor's speed as a function of said determinedconsumption rate.
 14. The device of claim 12 further comprising meansfor determining the emission rate of selected constituents from thecombustion process and means for varying said motor's speed as afunction of said determined emission rate.
 15. The device of claim 9wherein said bis-acetylacetonato platinum powder is diluted with afiller material, said filler material selected to have a particle sizeand density comparable to the bis-acetylacetonato platinum powder andfurther selected to sublime at between about 260° and 310° F.
 16. Thedevice of claim 15 wherein said subliming filler material is employed totransport said bis-acetylacetonato platinum in its highly dispersed,gas-transportable state into the combustion zone.
 17. The device ofclaim 16 wherein said filler material is vanillic acid.
 18. A device forenhancing the efficiency of an internal combustion engine in whichhydrocarbon fuel is consumed in a combustion chamber in order todiminish the emission of undesirable exhaust constituents includingcarbon monoxide and incompletely oxidized hydrocarbons, comprising:acontainer for storing a selected combustion enhancing substance in itssolid state, said substance selected for its ability to enhance thecombustion process at ppb-range concentrations and further selected forits convertibility into a highly dispersed, gas-transportable state uponheating; a heated surface maintainable at a preselected temperatures; apositive displacement pump for transferring a preselected quantity ofsaid substance onto said heated surface; a variable speed motor forcontrolling the transfer rate of said pump; and a gas stream fortransporting said substance converted into its highly dispersed,gas-transportable state into the engine's combustion chamber.
 19. Thedevice of claim 18 further comprising means for determining the rate offuel consumption and means for varying said motor's speed as a functionof said consumption rate.
 20. The device of claim 19 wherein theengine's intake manifold pressure is measured to approximate the fuelconsumption rate.
 21. The device of claim 18 wherein finely powderedbis-acetylacetonato platinum is the selected combustion enhancingsubstance and the heated surface is maintained at between about 260° F.and 310° F.
 22. The device of claim 21 wherein the gas stream fortransporting converted substance is prevented from contacting surfacesin excess of about 400° F. prior to entering the combustion chamber. 23.A method for enhancing the efficiency of a combustion process in which ahydrocarbon fuel is consumed in a combustion zone in order to diminishemission therefrom of undesirable compounds including carbon monoxideand incompletely oxidized hydrocarbons, comprising the stepsof:selecting a combustion enhancing substance that is in its solid phaseat ambient conditions said substance having the ability to significantlyenhance said combustion process at ppb-range concentrations and furtherbeing convertible into a highly dispersed, gas-transportable state;storing said substance in its solid state; variably converting saidsolid substance at a controllable rate into its highly dispersed,gas-transportable state; and transporting said converted substance,substantially immediately upon its conversion, to said combustion zone.24. The method of claim 23 further comprising the steps of determiningthe fuel consumption rate of said combustion process and controlling therate of converting said solid substance into its highly dispersed,gas-transportable state as a function of the determined fuel consumptionrate.
 25. The method of claim 23 further comprising the steps ofdetermining the emission rate of selected compounds from said combustionprocess and controlling the rate of converting said solid substance intoits highly dispersed, gas-transportable state as a function of thedetermined emission rate.
 26. The method of claim 23 wherein theconverting step comprises the step of heating said solid substance. 27.The method of claim 26 further comprising the step of employingcombustion air drawn into said combustion process for transportingcombustion enhancing substance in its highly dispersed,gas-transportable state to the combustion zone.
 28. The method of claim23 wherein the converting step comprises subliming said solid substance.29. The method of claim 28 further comprising the steps of selecting afiller material having a sublimation temperature comparable to thetemperature at which said combustion enhancing substance is convertedfrom a solid to its highly dispersed, gas-transportable state anddiluting said solid substance with said filler material prior tostorage.
 30. The method of claim 29 further comprising the step ofemploying the subliming filler material to transport the combustionenhancing substance in its highly dispersed, gas-transportable state tothe combustion zone.